Friday, July 9, 2010

BP / Gulf Oil Spill - Radar Comes Through Again

This satellite radar image taken by Envisat's ASAR sensor at 10:44pm local time on July 7 shows a large patch of oil extending north from the site of the leaking Macondo well, and an area of small slicks along the Mississippi shoreline:

Envisat ASAR radar image (black-and-white) taken July 7, 2010. Image courtesy of CSTARS.

A large dark area extending from west of Mobile Bay to beyond Panama City may include patchy oil slicks and sheen, as seen in this area on previous days. But it is also an area of calm winds; the surface wind speed was measured at Buoy 42012 at 1 meter per second, gusting to 2 m/s, at the time this image was acquired. That's on the low-end threshold for oil slick detection with radar imagery.

This infrared GOES weather satellite image taken within minutes of the radar image shows the skies are mostly clear in the area, with no sign of rainfall:

7 comments:

  1. The Univ. of Hawaii posted another computer simulation for the oil leak. It has the oil stopping at 120 days while the simulation goes for 360 days.

    It's on YouTube: /watch?v=lim0-gT7WDw

    ReplyDelete
  2. Why is it NOAA or CNN don't show the huge portion of the spill / slicks off the Florida coast like the radar image shows...they only have the smaller portion of the spill / slick off the coast of Louisiana identified on their maps? Are they trying to hide something that is apparent on your radar images? I was wondering why on CNN their tracker map made it look like the spill was actually shrinking in the last 2 weeks while skimmers weren't even in the water. This makes a lot more sense now - thanks Skytruth :)

    ReplyDelete
  3. bluerocks - that's a good question. That big area along the coast that we outlined with a dashed orange line is ambiguous: the wind speed was low when the image was taken, which tends to make water appear dark whether it is oil-covered or not. We decided to outline it as an area of "possible" oil slicks and sheen, because we've seen oil there on other recent images.

    Some of the "shrinkage" in the area covered by oil slick could be real: rough weather there since Alex went by could be breaking up and naturally dispersing the thinnest slicks and sheen located farther away from the leaking well. Or it could be due to limitations in the available satellite images: strong winds are able to kick up choppy waves in areas that are covered by very thin oil, making them appear medium-gray in color - similar to clean water.

    That's why it's tricky to draw conclusions based on just one or two images. We'll have to see if these trends continue in coming days.

    ReplyDelete
  4. Yay Youz Guyz! I found it! LANDSAT!
    http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/ETM
    However, novice me will have to learn how to use this so, if any of you have any suggestions of the way this sort of Satellite thing works, pointers to avoid stupid redundancies etc, I'd much appreciate it.
    Please leave me a note in the comments of The Ladder and don't try to email me from the blog's profile email address. That's for psycho-spammers run run run awaaaayyyy....

    I just want to be able to look down on the ground, the marshes, for oil, and follow the rainfall effects up into the Mid-South etc.

    Thanks youz
    Editilla~New Orleans Ladder
    http://noladder.blogspot.com/

    ReplyDelete
  5. Did y'all see this one yet?
    http://www.floridaoilspilllaw.com/latest-satellite-analysis-oil-miles-mexico-cancun

    ReplyDelete
  6. NOL - re Landsat - congrats, but the resolution (30m color) might not do the trick in terms of seeing oil in wetlands. But let us know if it works out.

    Re oil hitting the Yucatan - we're not so sure about this one. The current coming through the Yucatan straits generally goes from south to north, and not every dark area on a radar image is caused by floating oil. We'll have to see if there is any confirmation in coming days.

    ReplyDelete
  7. Thanks, John. I'm beginning to notice that with the LANDSAT resolutions. We'll see.
    Re oil in the Yucatan, I was also going on the latest WAVCIS reports on the LOOP Current taking a swing around the spill:
    http://wavcis.csi.lsu.edu/forecasts/forecasts.asp?modelspec=currents

    Editilla Out :)

    ReplyDelete